Which of the followng oxides is/are amphoteric/

Options

A. `Na_(2)O`
B. `CaO`
C. `Al_(2)O_(3)`
D. `SnO_(2)`

Answer

To determine which of the given oxides are amphoteric, we need to analyze each oxide based on its ability to react with both acids and bases. Amphoteric oxides can react with acids to form salts and water, and they can also react with bases to form complex ions or other products.

**Step-by-Step Solution:**

1. **Understanding Amphoteric Oxides**:
- Amphoteric oxides are defined as oxides that can react with both acids and bases. This means they can behave as either an acid or a base depending on the reaction conditions.

2. **Analyzing Na2O (Sodium Oxide)**:
- Sodium oxide (Na2O) is a metallic oxide. When it reacts with water, it forms sodium hydroxide (NaOH), which is a strong base.
- Reaction: Na2O + H2O → 2 NaOH
- Since Na2O only reacts with water to produce a basic hydroxide, it is classified as a basic oxide, not amphoteric.

3. **Analyzing CaO (Calcium Oxide)**:
- Calcium oxide (CaO) is also a metallic oxide. It reacts with water to form calcium hydroxide (Ca(OH)2), which is also a strong base.
- Reaction: CaO + H2O → Ca(OH)2
- Similar to Na2O, CaO is a basic oxide and does not exhibit amphoteric behavior.

4. **Analyzing Al2O3 (Aluminum Oxide)**:
- Aluminum oxide (Al2O3) is known to be amphoteric. It can react with acids and bases.
- Reaction with acid: Al2O3 + 6 HCl → 2 AlCl3 + 3 H2O
- Reaction with base: Al2O3 + 2 NaOH + 3 H2O → 2 NaAl(OH)4
- Since Al2O3 reacts with both acids and bases, it is classified as an amphoteric oxide.

5. **Analyzing SnO2 (Tin(IV) Oxide)**:
- Tin(IV) oxide (SnO2) is also amphoteric. It can react with acids and bases.
- Reaction with acid: SnO2 + H2SO4 → Sn(SO4)2 + H2O
- Reaction with base: SnO2 + 2 NaOH + 2 H2O → Na2Sn(OH)4
- SnO2 shows the ability to react with both acids and bases, confirming its classification as an amphoteric oxide.

6. **Conclusion**:
- Based on the analysis, the oxides that are amphoteric are Al2O3 and SnO2. Therefore, the answer is:
- **Al2O3 and SnO2 (options 3 and 4)**.